When the gate rolls open at a federal penitentiary in West Texas today, a man reputedly once a lieutenant for a top Mexican drug cartel, will be free.

If his old friends don’t find him.

Nearly eight years ago, Jose Manuel Garza Rendon walked across a bridge spanning the Rio Grande, surrendered to U.S. border guards and handed federal agents a golden opportunity. He snitched.

“Basically, he is going from a safe, secure environment to being a hunted rabbit,” said Mike Vigil, the U.S. Drug Enforcement Administration’s former chief of international operations and now a vice president at SOS International. “Unless he does a good job of staying on the run or going to an area where nobody knows him, they’ll kill him.”

Authorities won’t say if he will be deported to Mexico.

Until today, prisoner 11277-179, was just one of dozens of drug cartel members in U.S. custody after being captured or extradited, and prosecuted by U.S. authorities.

But Garza, now 56, was unique: He had rank and experience and a road map of one of Mexico’s most powerful criminal syndicates, the Gulf Cartel.

Before his capture, the U.S. government offered up to $2 million for his capture. Hitmen from his own cartel were looking for him too: They wanted to kill him for botching business while addicted to cocaine.

An FBI wanted poster described Garza, who had a sixth-grade education, as one of two cartel lieutenants. Fearing for his life, Garza gave up.

His surrender in 2001 was significant; he was the first person captured as part of an indictment developed from an investigation the Justice Department had been working on for years.

Big capture

Also wanted, and later captured in that case, was Osiel Cardenas Guillen, the cartel’s alleged kingpin, who is to be tried in federal court in Houston in September.

He is one of the biggest drug bosses ever to be extradited to the United States from Mexico and is accused of a host of drug-trafficking crimes as well as money laundering and threatening to kill two U.S. agents and an undercover sheriff’s deputy.

Court documents indicate the FBI and DEA debriefed Garza about his 13 years with the Gulf Cartel, including an incident in which gangsters surrounded and threatened to shoot two U.S. federal agents caught driving through the border city of Matamoros, with a confidential informant ducking down in the back seat, as they searched for cartel leaders’ homes.

Although a U.S. federal agent described what Garza revealed behind closed doors as “substantial” there is nothing in the public record to indicate specifically what he said.

There is also nothing to indicate he’s willing to testify against anyone, or if he even told the truth.

As part of his plea agreement, Garza pleaded guilty to conspiracy to possess with intent to distribute marijuana in a case in which he was snared by an undercover agent as he tried to collect payment for approximately one ton of marijuana delivered to Houston, according to court documents.

Out to defeat cartel

As Garza now faces an uncertain future, shaped by whether his enemies remember him, the U.S. and Mexican governments are working together like never before to dismantle the cartel and keep Cardenas behind bars.

Records don’t say what Garza told authorities about Cardenas, who was extradited to the United States shortly after President Felipe Calderon took office in 2006 on a vow to restore the rule of law.

“His extradition was a sign of things to come with the new administration,” Cardenas’ attorney Chip Lewis said. “Clearly, he was the biggest guy they had in custody.”

In 2008, there were a record 95 fugitives extradited from Mexico to the United States, 36 of whom were wanted for drug charges, according to the Justice Department.

In addition to Cardenas, two others charged in the case recently landed in Houston via extradition.

Ruben Sauceda Rivera, an assistant book keeper who tracked millions of dollars for the cartel, pleaded guilty in late March to money laundering.

Juan De La Cruz Reyna, decribed by Mexican prosecutors as a former state policeman who became a hitman, pleaded guilty the same day to threatening to assault the federal agents, who were surrounded by the cartel’s gunmen.

Tony Garza, the former U.S. ambassador to Mexico, said cartel members fear the United States.

“Extradition is a powerful tool. There are few places cartel members fear more than an American prison, and Calderon has been both fearless and aggressive in its use,” he said.

As his release from prison approached, inmate Garza declined two Chronicle requests for an interview. The Federal Bureau of Prisons wouldn’t discuss what will happen with him next.

But Vigil, the former DEA agent, said of Garza’s old cartel associates: “Just like the Italian Mafia, they don’t forget.”